1. Field of the Invention
The present invention relates to a dish washing machine for automatically washing and rinsing, for example, the dishes contained in a cavity.
2. Description of the Prior Art
A dish washing machine so adapted as to spray wash water on the dishes contained in a cavity to wash the dishes and dry in the cavity the dishes which have been washed is disclosed in Japanese Patent Laid-Open Gazette No. 48724/1985, for example.
This type of dish washing machine is so constructed that a part of the sidewall of a water suction pipe provided between a water storage chamber provided on the bottom of a cavity and the water suction side of a nozzle pump is made of a translucent material, and a light emitting element and a light receiving element for detecting the light transmittance of a liquid in the water suction pipe are disposed on the outside of the translucent sidewall, to control the time when each of the washing, rinsing, dehydrating and drying processes is terminated at the time point where the amount of light received by the light receiving element does not change.
In the dish washing machine disclosed in Japanese Patent Laid-Open Gazette No. 48724/1985 is so adapted as to measure the change in the transmittance and detect the time when the transmittance does not change to terminate each of the washing, rinsing, dehydrating and drying processes, as described above.
In the above described dish washing machine, however, the washed state of dirt adhering to the dishes is detected, while sequence control corresponding to the quality of the dirt is not carried out. Therefore, an oil film or the like may remain on the dishes which have been washed.
Therefore, a dish washing machine so adapted as to change the washing time and the washing temperature depending on the amount of dirt and the quality of dirt on the dishes has been proposed in Japanese Patent Laid-Open Gazette No. 49584/1993 by the applicant of the present invention.
In this dish washing machine, however, the contents themselves of washing and rinsing are the same, although the washing time and the washing temperature change depending on the degree of dirt on the dishes. Specifically, the dish washing machine includes processing for draining wash water at the same time that the wash water is supplied during washing and rinsing operations irrespective of the degree of dirt on the dishes to cause garbage accumulated on the bottom of a cavity to flow out. In addition, the dish washing machine includes processing for draining wash water at the same time that the wash water is supplied irrespective of the degree of dirt on the dishes during the washing and rinsing operations, stopping the washing and rinsing operations, and then draining the wash water for a predetermined time period to almost terminate the drainage of the dirty wash water, after which the subsequent rinsing operation can be performed using clean wash water. If the above described processing is not required because the degree of dirt on the dishes is low, therefore, it has become clear that water is uselessly used.